Fits a curve from a selection of vertices with a feature line, survey figure, parcel, or 3D polyline
Use this command to convert tessellated lines to true arcs, or to add fillets to straight segments. You can specify start
and end points or set options for automatic arc generation.
Tessellation occurs when you convert a 2D polyline with arcs to a 3D polyline. It also occurs when you export feature lines
with arcs from corridor models.
Grading created from tessellated footprint (left) compared with grading created from arc (right)
Feature line points that define a grade break are inserted as elevation points on the arc when using this command.
There are three ways to select the segments to turn into arcs.
- Automatic selection: As you move your mouse over the feature line, arcs appear where they can be inserted. Click your mouse to insert the arc.
- Specifying start and end points over multiple segments: Use this method to define an arc using specified start and end points.
- Specifying start and end points for a single segment: Use this method to replace a single segment (such as a chamfered corner) with an arc. If the corner is asymmetrical, two
arcs are inserted that are tangent to the line segments and to each other.
Arcs created at symmetrical (top) and asymmetrical corners (bottom)
You can specify the command options by editing the command settings, or by using the keyword when running the command.
To fit a curve
- Select the feature line or other object.
- Do one of the following:
- Move your mouse over the feature line. Arcs appear where they can be inserted. Click your mouse to insert an arc.
- Enter (P). Then select the start and end point on the feature line for the arc location. This option ignores the minimum number
of segments setting.
If the start and end points span more than one segment but the points do not define an arc, an error message is displayed
indicating that an arc cannot be created between the specified points. This error occurs if the segments do not all curve
in the same direction or if there is a straight segment that is composed of multiple small segments (which therefore have
no deflection angle).
If the segments can define an arc but are not within the tolerance, you are prompted with an option to override the tolerance
setting and insert the arc.
- Enter (O) to display the Fit Curve dialog box where you can change the tolerance and minimum number of segments settings.
- Feature lines
- Survey figures
- 3D polylines
- 2D polylines